Red thread in turf

Red thread is a disease of turfgrass that is often associated with under-fertilized turf and one of the simplest recommendations to alleviate disease pressure is to fertilize.

The excessive rainfall this spring has not only resulted in mowing challenges, but has also resulted in some turf areas in need of nutrition. Not surprisingly, reports of red thread (Laetisaria fuciformison) on lawns and landscape turf areas have been rolling in throughout the state. It seems that every year we observe red thread on lawns and often the outbreak follows the seedhead production period when the plant is probably looking for a little extra food. The common lawn-mix turfgrasses, Kentucky bluegrass, perennial ryegrass and fine fescue, are all susceptible.

Red thread is typically active during wet, moist periods when temperatures range from 55 to about 80 degrees. Red thread can be identified by the pinkish-red strands (slerotia) that extend from the leaf blade tip. If you observe the turf early in the morning when it is still moist, you might find what I describe as miniature balls of pink cotton candy. The areas infected by red thread will die and the turf may appear wilted.

Red thread can be mistaken for dollar spot in turf as the patchy type kill is very similar. This is one of those diseases you need to get on your hands and knees to check out to make sure you know that it is red thread. Fungicide applications are usually not necessary in dealing with red thread; a fertilizer application will often help the turf outgrow the damage.

Dr. Frank’s work is funded in part by MSU’s AgBioResearch.

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